Technics SL1200 G/GAE/GR Cartridge Alignment Overhang

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[Joerg]
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Technics SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by [Joerg] » 16 Apr 2019 16:59

I'm a bit unsure which method of cartridge-alignment is correct for the SL 1200 G.
If I use the Technics overhang-tool and then check the overhang with other methods, the values are not identical. With the Technics-tool I get about 2 mm too much overhang.
I do the counter-check with a two-point template, which would have to meet the Technics specifications.
(Inner zero 58.8 mm/overhang 15mm, outer zero 113.52 mm/22 ° offset angle, Pivot to Spindle 215 mm)
Even with the indirect overhang measurement (Scala "K " line "H ") of the Schön protractor, there is no match.
Does anyone have similar experiences?
Thanks.

JoeE SP9
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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by JoeE SP9 » 16 Apr 2019 17:41

It depends on which geometry the gauge or protractor was designed to use. At the top of the page go to Tools then Turntable setup. There are two tutorials that explain why there are differences and what they are.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by lenjack » 16 Apr 2019 17:53

The Technics supplied tool is strictly designed for Stevenson alignment, which gives minimal distortion at the innermost groove position of the record, where it is most critical.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by [Joerg] » 16 Apr 2019 19:57

Hello and thank You very much. I did not want to reopen an article here about Philosophies of Cartridge Alignment.
I am aware of The Differences. The Question is, can I set exactly 15 mm Overhang with the Plastic Technics tool, or not?
With the Schön-template, the Overhang can be measured independent by the Orientation philosophy.
The Qwin template includes the Technics alignment with a inner nullpoint 58.8 mm. This Value is calculated using the Alignment Calculator Pro, when the Specifications of the Technics tonearm are entered.
If you align the cartridge with it, that should be in reality 15 mm Overhang.
If I check afterwards with the Technics Tool, it's only 13mm Overhang.
What's right? What is wrong. There can only be one Truth.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by Japi Roelofs » 16 Apr 2019 22:24

Have you tried Conrad Hoffman's program to make a custom arc protractor?

I made an arc protractor using the Technics specifications. In order to get the program to produce a Stevenson protractor with the 58.8 and 113.5 mm null points, I had to alter the outer groove dimensions to 140.63 mm. Which seems kind of strange, but that's another story. Effective length was at 230 mm, overhang at 15 mm, and offset angle 22° exactly.

When I compared this protractor with a cartridge that I set up using the Technics gauge (using a fine scalpel blade pressed against the edge of the gauge, at a straight angle, to set the stylus distance) I got a perfect match. Well perhaps not a 100% perfect match, but the stylus was always on the arc line wherever I placed it, and most certainly not 2 mm off.

There are always small factors that can influence the outcome. For instance with the Technics gauge, the stylus distance is measured while the cantilever is 'pre-loaded': it will deflect once it's on the surface of the protractor. Also when the headshell is connected to the tonearm, the rubber washer will be compressed. And how accurate is my printer anyway?

But to me the outcome seems quite alright...

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by Alec124c41 » 17 Apr 2019 00:26

"There can only be one truth."
Wrong.
There are different alignment protocols that serve different priorities. The Stevenson, for instance, minimizes distortion on inner grooves, at the expense of overall minimum distortion, and would serve best for records with extended playing time, thus smaller inner grove radius.
Baerwald is calculated to give lower overall average distortion, but would not be as good as Stevenson with records that might get down to 53mm inner groove radius.
And if you only play the 7-inch 45s, you would want a completely different alignment.
The Baerwald alignment is typically about 2mm longer than the Stevenson, and sets the cartridge at a slightly different angle. Neither is wrong.
It is easy enough to try the different alignments for yourself. If you hear a difference, use the one that you prefer.

Cheers,
Alec

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by [Joerg] » 17 Apr 2019 04:57

@Japi Roelofs

Thank you for comparing these two methods. No, I didn't test the Conrad Hoffman's Protractor. Only the "Qwin" with identical null points, an Arc Protractor that I made myself and the Overhang measurement with the " Schön II " - template.
The Validity of the Printouts, i checked with an accurate Electronic Caliper. (0.00 mm)
What Technics do you have? One of the older 1210 MK ... or a current one.
The Material thickness of the Headshell in the Area of the SME Mount is also interesting.
There could also be differences between the newer and older models.
I cannot determine the tolerance of the exact Length of the S-Shape Tonearm.
The Distance pivot to spindle seems to be correct at 215 mm.
Unfortunately, the Technics Overhang gauge does not include the Tolerances in the real world.
Greetings.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by chiz » 17 Apr 2019 09:27

According to the manuals the tonearm geometry of the 1200G is indeed identical to the 1200MK2 etc.
The current Technics gauge has a different part number to the old one (RMR2210-W vs SFK0135-01).
It would be disappointing if the new gauge was inaccurate.
I prefer to use a protractor myself as I feel it gives a greater potential for accurate results.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by [Joerg] » 17 Apr 2019 21:04

Hello chiz. I think the Technics gauge has correct dimensions. I measured the gauge and was able to detect 52 mm.
I also think that a two-point template can provide more accurate results. The results are independent of tolerances in the production of the turntable.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by georgesgiralt » 17 Apr 2019 23:32

Hello !
IMHO the gauge is useful in positioning the cart in the head shell before adjusting it properly and exactly using the protractor of your choice. It is also convenient to hold the thing while putting the screws and nuts in place.
Just my 2 ¢

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by lenjack » 17 Apr 2019 23:52

If it gives me lowest distortion at inner grooves...mission accomplished. :!: =P~ =D>

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by Shadowman82 » 20 Apr 2019 22:31

Isn't it true that the Technics alignment achieved with the gauge is close to but not exactly Stevenson ? If that's the case then it would not be quite identical when you recheck it with a Stevenson protractor afterwards .

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by lenjack » 20 Apr 2019 22:34

Good question. Perhaps someone will let us know.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by chiz » 20 Apr 2019 23:16

As Japi said a few posts back, you can derive the Technics geometry from Stevenson calculations if you set the inner groove radius to 58.8mm and the outer groove radius to 140.62mm or thereabouts.

A Stevenson protractor derived from any of the standard inner / outer groove measurements (DIN, IEC etc) will not match the Technics geometry exactly.
Last edited by chiz on 20 Apr 2019 23:26, edited 1 time in total.

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Re: TECHNICS SL1200 G/GAE/GR Cartridge Alignment Overhang

Post by Sterling1 » 20 Apr 2019 23:18

Here's the bottom-line, if you want the Technics Turntable to produce the specified alignment/error result then align the cartridge to Technics instructions: 52mm stylus to headshell tail distance, and cart made parallel to axis of headshell.

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